Louison dreads going back to school for sixth grade--but luckily she's able to transform herself into a super-heroine named Wonder Pony to keep watch over the school and rid it of its mysterious monsters! Middle school wasn't exactly stable before, but it becomes a real struggle when sixth grader Louison is given the strength and powers of a pony by...a tiny pink toy pony that insists on being called Jean-Pierre? Now, Louison is saddled with the responsibility of reining in the monsters that are up to no good in her new school! It's time to horse around with Wonder Pony!